Content marketing is all the rage, dictating that I should help people solve problems -- that I should serve, not sell. But if I'm doing the heavy lifting for would-be customers, why will they buy from me? Why buy the cow when you can get the milk for free?
Some companies worry that by creating content and sharing it freely, they are giving away their thought leadership or trade secrets. They worry that competitors are trolling their blogs, gaining valuable insights or (worse!) poaching clients from the comment threads. For example, a CPA might worry that a blog post decoding some new Financial Accounting Standards Board rule for the small-business owner might result in clients deciding they can handle their taxes on their own this year.

The truth is that giving away free content will do a few things, but none of those will dissuade the purchase of any metaphorical milk. Rather, educating prospects about the products you sell and underscoring your own expertise actually increases your credibility and fosters trust. You show that you know what you're talking about, and those who dig your stuff will become more educated and ready leads for sales.

And besides: The kind of clients who are inclined to do their own taxes would never buy accounting services anyway. Just sayin'.

I am on Facebook and Twitter, answering questions and engaging. Do I really need to be producing longer-form content? People are impatient, and their time is fractured.
I don't think of short vs. long-form content as an either/or prospect. Most businesses need both in their content-marketing mix. The trick is to use quick-hit, brief bursts of content (blog posts or social media updates) to answer easy questions and increase engagement.

Use longer-form material when your aim is to dig deeper into a topic, advise on a nuanced or complex issue or when an idea is special enough to warrant it.

In both cases, respect your audience. Long-form should never mean long-winded. Don't waste your audience's time by taking too long to get to the point--that's just self-indulgent. Clarity and brevity should rule, even when the content is multifaceted or complex. (Side note: That's why editors are important.)

I don't have the budget or time for anything more than a single content-marketing platform. What should it be--a blog, video, e-book or what?
I don't think a company can live without a blog (or a flexible content-management system that's blog-like), in the sense that it allows you to publish and amplify content easily and quickly. If you have to call someone in IT every time you want to publish something new to your website, that's adding an unnecessary level of complexity that dissuades creation.

How can small-business owners or startups make time to fit content marketing into their day?
Stop doing things that don't work, and start creating content. Find one business problem or marketing challenge and launch a content program around that specific issue. Identify proper metrics so you'll know whether it's a success, and give yourself a long enough period to measure the results. Content is a long-term commitment, not a one-and-done campaign.

I struggle with too much data. What's the one metric I should watch consistently?
I'll assume you're keeping an eye on your balance sheet, and that you are talking marketing metrics here? For that, there's no magic data elixir that applies to all businesses. If there were, I'd bottle it in beautiful packaging and drive around the country, trading it out of the back of my car for ounces of gold.

It's more important to figure out which marketing metric matters to you. It might be sales, but it might be something else, too: customer engagement or sharing metrics, or the length of time between lead generation and a sale. In other words, it depends. But at a high level, look at your lead-gen, sales and sharing metrics. Those are the ones that will give you a pretty solid sense of how well your marketing is driving business.